diff --git a/sanguo_factor/universe.py b/sanguo_factor/universe.py
index ce7fd13..aa7714e 100644
--- a/sanguo_factor/universe.py
+++ b/sanguo_factor/universe.py
@@ -10,9 +10,10 @@ from datetime import datetime, timedelta
 
 import polars as pl
 
+from sanguo_data.datareader import guess_exchange
+
 STOCK_PREFIXES = ("60", "00", "30")
 WARMUP_BARS = 120
-_CHUNK = 300          # 分块 IN 查询每块 symbol 数(控瞬时内存)
 _LOOKBACK_DAYS = 300  # start 前缓冲(覆盖最大 60 日窗口 + 节假日)
 _FORWARD_DAYS = 45    # end 后缓冲(覆盖 10 日前瞻收益)
 
@@ -37,11 +38,16 @@ def load_universe_bars(
     if symbols is None:
         conn = sqlite3.connect(vnpy_db, timeout=60)
         try:
-            # 无过滤 DISTINCT symbol 走 (symbol,...) 前导索引顺序流式扫——
-            # 带 WHERE(interval/datetime/LIKE)的版本会退化为 26G 全表扫(NAS 实测>5min)。
-            # 前缀在 Python 侧滤;interval='d'/窗口过滤由下方分块数据查询天然承担
-            # (无日线数据的 symbol 返回 0 行,不进最终 df,语义不变)。
-            cur = conn.execute("SELECT DISTINCT symbol FROM dbbardata")
+            # 松散索引扫(递归 CTE):每符号一次 seek(NAS 实测 70s vs 朴素 DISTINCT 573s——
+            # 34M 索引条目 2核NAS 走不完;seek 次数=符号数≈7700)
+            cur = conn.execute(
+                "WITH RECURSIVE s(sym) AS ("
+                " SELECT min(symbol) FROM dbbardata"
+                " UNION ALL"
+                " SELECT (SELECT min(symbol) FROM dbbardata WHERE symbol > s.sym)"
+                "   FROM s WHERE s.sym IS NOT NULL"
+                ") SELECT sym FROM s WHERE sym IS NOT NULL"
+            )
             symbols = [r[0] for r in cur if str(r[0]).startswith(STOCK_PREFIXES)]
         finally:
             conn.close()
@@ -52,16 +58,16 @@ def load_universe_bars(
         symbols = sorted(random.Random(42).sample(symbols, limit))
 
     chunks: list[pl.DataFrame] = []
-    for i in range(0, len(symbols), _CHUNK):
-        part = symbols[i : i + _CHUNK]
-        ph = ",".join("?" * len(part))
-        conn = sqlite3.connect(vnpy_db, timeout=30)
+    for sym in symbols:
+        ex = guess_exchange(sym).value  # "SSE"/"SZSE";60→SSE,00/30→SZSE 与入库一致
+        conn = sqlite3.connect(vnpy_db, timeout=60)
         conn.execute("PRAGMA busy_timeout=30000")
         try:
             cur = conn.execute(
                 f"SELECT {_COLS} FROM dbbardata "
-                f"WHERE interval='d' AND datetime>=? AND datetime<=? AND symbol IN ({ph})",
-                (lookback_start, forward_end, *part),
+                "WHERE symbol=? AND exchange=? AND interval='d' AND datetime>=? AND datetime<=? "
+                "ORDER BY datetime",
+                (sym, ex, lookback_start, forward_end),
             )
             rows = cur.fetchall()
         finally: